This invention relates to methods and devices practiced and used in the collection, preservation, transportation and analysis of biological tissues and bodies, and more specifically to instruments used for collecting specimens of fecal matter or other similar biological material.
Several devices and methods have been used in the past to collect, preserve and transport and dispense biomedical specimens including fecal samples for later analysis by a laboratory or for clinical studies. The most common has been a smear paper pad, upon which, in the case of fecal samples, three consecutive specimens are smeared, covered then sent for analysis. One of the most common problems associated with this device and method is dehydration. Even under rehydrating condition, a fecal occult blood test of dry samples on paper pads will give false positive or negative results. A false positive result may trigger a relatively expensive colonoscopic or barium enema examination that will probably or eventually eliminate the false diagnosis. In the case of a false negative result, an early stage colorectal cancer may be missed, and if then metastosis occurs, the cancer may become incurable.
Another fecal sample collection device of the prior art comprises a simple cylindrical tube with a cap having a breakable tip and a plastic stick connected to the inside of the screw cap. The tube contains a certain amount of extraction buffer. The stick is inserted into fresh feces several times then put back into the tube and the cap is tightly secured to seal the tube. The main advantage of this procedure is that the extraction buffer keeps the specimen wet and a preserving reagent mixed therewith may slow down the degradation of the biological molecule or its markers. While this method constitutes a substantial improvement over the smear paper devices of the past, unintended breakdown of the tip on top of the cap has occurred during manipulation of mailing of the specimen resulting in leakage and possible contamination. Moreover, specimens have a tendency to include excessive amounts of fecal material for the amount of preservative or reagent contained in the tube resulting in false positive analysis. Another improved device of the prior art is disclosed in U.S. Pat. No. 6,063,038 Diamond et al. In this case, a filtering membrane is provided between the body of the shipping vessel which holds the specimen and a preserving/reagent solution and the hollowed inside of the stick itself which can be accessed through a self-sealing membrane to extract a part of the liquid containing only the amount of specimen that passed through the filtering membrane. This improved device still suffers from a high risk of spillage of the preservative/reagent and a lack of quantitative mixing of the sample and preserving/reagent fluid.
The instant invention results from some attempt to provide a practical solution to the problems and disadvantages of the aforesaid devices of the prior art.
The principal and secondary objects of this invention are to provide a convenient, safe and inexpesive to manufacture device and method for collection by a patient or unskilled person of fresh fecal or other biological specimens in a quantitatively metered manner and for the preservation and leakproof shipping of the specimen through the mail to a laboratory for further analysis while avoiding degradation of the specimen through dehydration or imbalance combination of specimen and preserving agents.
These and other valuable objects are achieved by providing a simple tubular vessel closed at one end by a breakable hollow nib or other releasable sealing device that is engaged at the opposite end by a cap or stopper from which a stick axially projects into the vessel. At the distal end of the tip, a sample-holding portion has at least one radial or axial cavity and preferably indentations in the form of a spiral or helicoidal groove. As the stopper and stick are progressively inserted into the vessel by a screwing movement, the sample-holding portion passes through an aperture defining a narrow channel in the center of a septum in the median section of the vessel. The cross-section of the non-grooved part of the sample-holding portion closely match the cross-sectional profile of the aperture so that any access specimen matter which is not contained within an indentation, whether a cavity or groove, is conveniently wiped out and prevented from passing into the most distal chamber of the vessel that contains a preserving fluid. The shank of the stick right behind the sample-holding portion seals the specimen-holding chamber so that the amount of specimen and preserving fluid are quantitatively balanced and remain so until part or all of the fluid is extracted for analysis after breaking of the sealing nib. A cover, shaped and dimensioned to safely cap the breakable nib can be tightly screwed upon the closed end of the vessel to protect the nib during manipulation and shipping of the device. The specimen-holding chamber is thus doubly sealed at opposite ends to ensure against leakage both before and after specimen collection. A padded shipping container made from inexpensive disposable plastic provides a third seal and enhanced protection.